The image is equally critical across multiple zones of thought: the history of British art, the history of science, and-–perhaps unexpectedly—political theory.
Mezzotint is the most laborious process of intaglio printmaking, the mode of artistic creation in which printmakers use an engraving burin to cut directly into the copper-plate matrix from which the final reproducible image emerges.
With intaglio, great pressure is needed when printing. Because the ink for the image lives in the lines the printmaker cuts into the copper plate, the paper when cranked through a press must be pushed powerfully against the plate to meet the networked canyon of lines the matrix comprises.
With mezzotint intaglio printmaking, the artist works from darkness into light. With a special tool called a rocker, they grind the originally untouched copper plate into a rough basis with which to work. If printed at this point, ink would catch everywhere, and the work would be entirely negative space.
It is only after the mezzotint engraver subsequently crafts the image by incising lines into the rough surface they have created that an image can appear. The result is always dramatic, defined by rich contrasts of light and dark.
examples of mezzotints
Importantly, Green’s A Philosopher Shewing an Experiment on the Air Pump was an image that reproduced an existing painting, Joseph Wright of Derby’s An Experiment on a Bird in the Air Pump, completed in 1768.
Historically, the scene comprises one that took place across many well-to-do homes in Georgian England. A traveling philosopher conducts a demonstration making visible normally invisible natural phenomena. Here, perhaps cruelly, he is demonstrating the vitality of air and breath on a pet cockatoo who has been taken from his cage to the right and placed into an air pump in the center as an artificial vacuum effectively made devoid of oxygen.
Vitally, I believe, the drama of the scene is heightened by Green’s mobilization of mezzotint in print over Wright’s original marshalling of paint on canvas. This extends the image’s impact as not only an object of artistic contemplation, but a means of scientific inquiry and critical theory.
The mezzotint was published by John Boydell, who worked in Cheapside in London. His shop was next door to Joseph Johnson, the key publisher of radical philosophy in Romantic-period London. Johnson published Joseph Priestley’s first edition of his Experiments and Observations on Different Kinds of Air in 1774. In it, Priestley describes the series of experiments using air pumps through which he made his principle discovery of oxygen, instantiating the scientific field of pneumatic chemistry.
In a new preface appended to later editions of the work, he transposed his pneumatic chemistry discovery into the field of political theory, writing:
And the English Hierarchy (if there be any thing unsound in its constitution) has equal reason to tremble even at an air pump.
Priestley’s point was that understanding breath is to apprehend the grounds of egalitarian thinking. All things great and small require oxygen to live. It would seem then that powerful objects-driven aesthetic affects of Green’s mezzotint contributed to the scientific and political force of Priestley’s science and theory.
The question now is how continuing to think about breath through object might contribute to new conceptualizations of air in our time of atmospheric disruption, through climate change, and respiratory illness, with COVID-19.
—Jacob Henry Leveton, 2019–20 COSI Research Fellow